1. Field of Invention
The subject matter herein relates to improvements in the production of activated carbon, metakaolin, cement clinker, and improved combination products resulting therefrom, such as fly ash.
2. Description of the Related Art
Recent regulations governing the capture and reduction of mercury emissions from coal fired applications have led to testing of numerous materials suitable for mercury capture. A leading mercury capture technology utilizes activated carbon which can be doped with, for example, bromine.
This activated carbon, when injected in the flue gas stream of a coal-fired furnace, will capture the mercury and in most cases be filtered out of the gas stream with the coal fly ash. This fly ash in many applications, and most notably large utility coal-fired boilers, is often utilized in the production of Portland cement.
Depending on the activated carbon source and characteristics, the added carbon content of the fly ash can adversely increase the foaming index of the concrete, making the previously suitable fly ash fly ash unsuitable for concrete applications. Numerous investigations are underway to produce an activated carbon with a low foaming index or to develop an additive that can compensate for the foaming characteristics of a particular activated carbon.